System and method for facilitating diagnosis and maintenance of a mobile conveyance

ABSTRACT

A system for facilitating diagnosis and maintenance of a control networks on a mobile conveyance comprises one or more wireless ground stations configured to communicate over a wireless communication channel with the control network. A local area computer network receives and responds to messages to or from the control network via the wireless ground stations. The local area computer network may have user terminals, a server computer, a database comprising diagnostic information relating to said control network, and a replacement parts database and/or job auction database. The local area network may also include a wide area network interface, allowing diagnostic information for the control network to be retrieved or parts to be ordered from remote vendor sites. The system may also include wireless handheld, portable equipment for allowing service personnel to perform diagnostic analysis, maintenance, and testing of the mobile conveyance control network.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/787,662 filed May 26, 2010, which is a continuation of U.S.application Ser. No. 10/165,384 filed Jun. 6, 2002 (now U.S. Pat. No.7,734,287), which is a continuation-in-part of U.S. application Ser. No.09/592,021 (now U.S. Pat. No. 6,757,521) and Ser. No. 09/593,170 (nowU.S. Pat. No. 6,847,916) both filed on Jun. 12, 2000, both of whichclaim the benefit under 35 U.S.C. §119 of PCT Application Ser. No.PCT/US00/09644 filed on Apr. 10, 2000, all of which are herebyincorporated by reference as if set forth fully herein.

BACKGROUND OF THE RELATED ART

1. Field of the Invention

The field of the present invention relates to electronic diagnostic andmaintenance tools for control networks.

2. Background

Electronic control systems are commonly used in a number ofmanufacturing, transportation, and other applications, and areparticularly useful to control machinery, sensors, electronics, andother system components. Manufacturing or vehicular systems, forexample, may be outfitted with a variety of sensors and electricaland/or mechanical parts that may need to be activated, deactivated,monitored, enabled, disabled, adjusted or otherwise controlled whenneeded to perform their predefined functions. Control of the varioussystem components is generally accomplished by providing suitableelectronic signals to various actuators, relays, switches, or othercontrol points within the system. Control systems often require thatprocesses be carried out in a prescribed order, or with a level ofresponsiveness, that precludes sole reliance on manual control. Also,such systems may employ sensors or other components that requirecontinuous or periodic monitoring or control, and therefore lendthemselves to automated or semi-automated control.

A variety of different network architectures for controlling electronicsystems have been developed or proposed. Examples of various controlnetworks include programmable logic controller (PLC) based multiplexedcontrol systems in which a single central processing unit (CPU) is usedto control a number of input/output (I/O) modules or network nodes;network-controlled multiplexed control systems in which a network ofinterconnected CPUs are used to control a number of I/O modules at thevarious network nodes; and hierarchical, master-slave multi-bus controlsystems, wherein CPU-driven network nodes are connected together at eachbus level in a loop configuration.

In most control networks, it is necessary to be able to diagnoseoperational problems that may occur within the system. Operationalproblems may result from wiring faults, component failures (either inthe control network or in the components being controlled by the controlnetwork), or logic flaws, among other reasons. Also, it may be necessaryto test the operation of the controls system from time to time, such aswhen components are added or removed, or when functionality of thecontrol system is added or changed.

Traditionally, diagnosis and testing of a control network is carried outby manual activation of switches, relays or actuators, and observing theresults on the input/output devices of the control system. Conventionalmeters (e.g., an Ohm-meter) may be used to determine if electricalsignals from the control network are reaching the intendeddestination(s). Due to the different types of operational problems thatcan occur (e.g., wiring fault vs. component failure), and the myriad ofpossible places in which a fault or failure could occur, locating thesource of an operational problem can be an extremely slow and laboriousprocess. With the increasing complexity of control systems and thesteadily growing number of components used in such systems, diagnosisand testing become even more critical and, in many respects, moredifficult.

To conduct a complete manual test or diagnosis of a control system canbe very time consuming and tedious. The test personnel generally need toread complicated circuit blueprints and locate each relay, switch,actuator or other component that needs to be tested. Often, multiplerelays, switches or actuators will need to be activated, switched orotherwise positioned to test a particular system component. In such acase, the test personnel needs to locate and set each such relay, switchand/or actuator to its proper position, which can be a lengthy process.In many control systems, simply locating the appropriate switches,relays or actuators can be difficult, especially if the control systemis complex and includes many components. Also, particularly in the caseof on-board control systems used in vehicles (such as buses or railcars), the switches, relays or actuators can be located in inconvenientplaces and thus hard to find or set to reach manually.

Diagnosis and testing of a control network is sometimes carried out byconnecting a test computer (usually a laptop or other portablecomputerized device) to a diagnostic and maintenance port of the controlnetwork. The test computer is generally programmed to receive varioustypes of information from the control network to allow an operator tomonitor the functioning of the control system. The test computer mayalso be used to download new programming instructions to the controlnetwork via the diagnostic and maintenance port.

An illustration of a test computer set-up for monitoring a controlnetwork is illustrated in FIG. 1. As shown in FIG. 1, a vehicle 101(shown in phantom for convenience of illustration) has a control network110 (shown in solid, dark lines) with various I/O modules dispersedthroughout the vehicle 101. A test computer 103 connects by a cord 106to a module 112 containing the diagnostic and maintenance port. The testcomputer 103 is thereby able to monitor the functioning of the controlnetwork 110.

FIGS. 2, 3 and 4 are diagrams of test computer set-ups for differentcontrol networks as known in the art. FIG. 2 illustrates a hierarchical,master-slave control network 120, having a master bus controller (MBC)125 connected to a common bus 138, which connects various network nodesin a loop configuration. The network nodes may include, for example,high-speed cell net controller (HCNC) modules 128 and digitalinput/output (DIO) modules 127, or other types of modules, all of whichgenerally operate in a slave mode with respect to the common bus 138.The control network 120 may also include one or more secondary buses(not shown). Further information about certain types of hierarchical,master-slave control networks may be found in U.S. Pat. Nos. 5,907,486and 6,061,600 and Japanese Patent documents 10-326259 and 10-333930, allof which are assigned to the assignee of the present invention andhereby incorporated by reference as if set forth fully herein. Thecontrol network 120 may be physically connected to a test computer 123from time to time through an RS-485 compatible diagnostic andmaintenance port 129, for the purpose of testing and monitoring thefunctionality of the control network 120 as generally described above.

FIG. 3 is a diagram of a PLC-based multiplexed control system 140, inwhich a single main central processing unit (CPU) 146 is used to monitorand control a number of network nodes 150 in a control network 145. Eachnetwork node 150 typically includes a programmable logic controller(PLC) which, in turn, monitors various input signals or conditions (suchas temperature, current, speed, pressure and the like) and generatesoutput signals to various output devices (such as actuators, relays orswitches) through input/output (I/O) modules 152, thus providinglocalized control at various network node sites. The main controlnetwork CPU 146 communicates with the PLCs of each of the network nodes150 over a main system bus 147, and provides top-level command andcontrol. The main control network CPU 146 may be physically connected toa test computer 149 from time to time through an RS-232 compatiblediagnostic and maintenance port 148, for the purpose of testing andmonitoring the functionality of the control network 145 as previouslydescribed.

FIG. 4 is a diagram of a network-controlled multiplexed control system160 in which a network 165 of interconnected CPUs 170 are used tocontrol a number of I/O modules 172. A main CPU 166 is connected toother dispersed CPUs 170 over a control area network (CAN) bus or devicenet 167. The CAN bus or device net 167 may be physically connected to atest computer 169 from time to time through a CAN bus or device netgateway 175, which connects to the CAN bus or device net 167 through aCAN bus or device net test port 168. Testing or monitoring of thefunctionality of the control network 165 may thus be carried out, aspreviously described.

While the use of a computer to monitor the functioning of a controlsystem has some advantages, present systems have limitations anddrawbacks. For example, the test computer generally must be kept closeto the diagnostic and maintenance port, due to the cord 106 (as shown inFIG. 1) connecting the test computer to the diagnostic and maintenanceport. This arrangement physically limits where the test personnel canview relevant information. Thus, test personnel working at the back ofthe vehicle 101, for example, could not view the information being shownon the test computer 103. Therefore, the test personnel would need towalk back and forth between the test computer 103 and the pertinentlocations of the vehicle 101 in order to carry out an ongoing test ordiagnostic procedure. Further, the test personnel often need to refer tocomplicated circuit blueprints to interpret the information on the testcomputer 103 and to locate the various locations of interest within thecontrol network 110 of the vehicle 101. Such blueprints are usually inpaper form and are cumbersome to deal with. Cross-referencing betweenthe circuit blueprints and the information on the test computer 103takes extra time and effort on the part of the test personnel, and maybe the source of human error in conducting a test or system diagnosis.Further, the types of testing, monitoring and diagnosis that can beconducted using a test computer 103, at least as conventionallypracticed, are limited.

Some systems for wireless diagnosis or monitoring have been proposed incontexts such as diagnostic analysis of an automobile or similarvehicle. Examples of such wireless systems may be found in U.S. Pat.Nos. 5,758,300 and 5,884,202. Conventional wireless diagnostic andmonitoring systems typically involve a portable wireless unit that isspecifically configured for a single type of application. Therefore,such portable wireless units are useless for monitoring systems otherthan the type for which they are specifically configured. Creating acustom portable wireless unit for each type of control network can beexpensive and time-consuming. Also, despite being wireless, the type ofinformation and test functionality they provide is limited, and most, ifnot all, such wireless systems do not have the functionality to operatein the context of a sophisticated control network.

Additionally, conventional diagnostic systems generally provide littletechnical assistance to, or control over, maintenance personnel whoservice on-board control networks used in vehicles. Rather, amaintenance engineer generally relies upon whatever information he orshe can carry, typically in the form of manuals, blueprints, guidebooksand the like. These types of materials, as noted, are cumbersome, andmay require the maintenance shop to maintain a large library oftechnical publications if many different types of vehicles are to beserviced.

Therefore, a need presently exists for a flexible, versatile and simpleto use test and diagnosis tool suitable for either simple or complexcontrol network systems. Further, a need exists for improving technicalassistance to maintenance personnel, and for reducing the need forkeeping large libraries of printed technical publications.

SUMMARY OF THE INVENTION

The invention provides in one aspect systems and methods for monitoring,diagnosing, and/or testing a control network using portable, wirelessdiagnostic equipment, as well as systems for providing remote access todiagnostic information or replacement parts or related information overa wide area network.

In one or more embodiments as disclosed herein, a system and method forfacilitating diagnosis and maintenance of one or more control networkslocated on a mobile conveyance comprises one or more wireless groundstations configured to communicate over a wireless communication channelwith a control network via a wireless interface. A local area computernetwork receives and responds to messages to or from the control networkvia the wireless ground stations. The local area computer networkcomprises one or more user terminals, a server computer, a databasecomprising diagnostic information relating to said control network, and,optionally, a replacement parts database and/or job auction database.The local area network further includes a wide area network interface,which allow either additional diagnostic information relating to thecontrol network to be retrieved, or parts to be manually orautomatically ordered from remote vendor sites. The system may alsoinclude wireless handheld, portable equipment capable of communicatedwith the local area network and/or wide area network, for allowingservice personnel to perform diagnostic analysis, maintenance, andtesting of the control network(s).

In certain embodiments, the portable electronic diagnostic equipmentcomprises a portable, wireless intermediary device connected to adiagnostic device which is programmed to allow for diagnosis and testingof a control network. The diagnostic device preferably is embodied as apersonal digital assistant (PDA) preferably comprising, among otherthings, an on-board computer and a graphical screen display. Theportable, wireless intermediary device includes a line interface (eitherserial or parallel) to the diagnostic device, and receives, formats andmodulates the output of the diagnostic device for communication over awireless channel to a wireless interface unit connected to the controlnetwork. The portable, wireless intermediary device thereby enableswireless communication between the diagnostic device and the controlnetwork, allowing testing, monitoring and/or diagnosis of the controlnetwork.

In certain embodiments, the portable, wireless equipment is programmedto test, monitor and/or diagnose a control network. The portable,wireless equipment preferably comprises a graphical screen display fordisplaying images to the operator useful for testing, monitoring and/ordiagnosing the control network. The displayed images may include anillustration of all or part of the control network within the context ofthe facility (e.g., building, vehicle, plant, robot, machine or otherfacility), to facilitate the operator's testing, monitoring and/ordiagnosis of the control network. The image of the facility may bepresented on the graphical screen display in “phantom” to allow theoperator to easily view the components of the control network beingobserved or tested.

In another embodiment, the portable, wireless equipment is programmed toallow the operator to force individual system components to a desiredoutput state. By entering various inputs, the operator causes testcommands to be conveyed wirelessly from the portable, wireless equipmentto the control network, whereupon the test commands are relayed to theappropriate system component. If working properly, the system componentchanges state to the desired output state. The portable, wirelessequipment is preferably programmed to receive feedback from the controlnetwork over the wireless connection, and to display the states of therelevant switches along the output path to the system component beingtested or observed. The portable, wireless equipment is programmed withinformation pertaining to the connections and locations of thecomponents in the control network, thereby simplifying diagnosis ortesting by the operator, and reducing or eliminating the need for theoperator to carry and interpret bulky, cumbersome manuals and circuitblueprints.

In other embodiments, the portable, wireless equipment includes anautomated procedure for testing a line connection between a diagnosticdevice carried by an operator and a portable, wireless intermediarydevice which facilitates wireless communication to the control network.The portable, wireless equipment may also include an automated procedurefor testing the wireless connection between the portable, wirelessintermediary device and the control network.

When used in conjunction with the local wireless communication network,location tracking of the portable electronic diagnostic equipmentpermits the “phantom” images of the control network to be orientedrelative to the position of the diagnostic device operator. Rotation ofthe phantom image display of the control network relative to theposition of the operator may provide a clearer, less obstructed view ofthe control network being observed or tested, and thus facilitate thediagnostic or test procedures being carried out by the operator.

In other embodiments, the local wireless communication network allowsmonitoring and control of actions carried out by maintenance personal,by allowing monitoring and control of electronic activity of theportable electronic diagnostic equipment. This functionality allowsground station supervisors to observe and record actions by maintenancepersonnel, to provide immediate feedback to maintenance personnel, andto override, if necessary, actions being taken by the maintenancepersonnel using the portable electronic diagnostic equipment. Amongother things, such functionality enhances the overall security of thediagnostic and testing system.

Further embodiments, variations and enhancements are also describedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a control network diagnostic techniqueas known in the prior art.

FIGS. 2, 3 and 4 are diagrams of different control networks as known inthe art.

FIG. 5 is a diagram illustrating a control network diagnostic techniquein accordance with a preferred embodiment as disclosed herein.

FIG. 6 is a top-level diagram of a remote diagnostic system inaccordance with a preferred embodiment as disclosed herein.

FIGS. 7, 8 and 9 are diagrams of the remote diagnostic system of FIG. 6as applied to various different types of control networks.

FIG. 10 is a diagram of a preferred wireless intermediary unit forconnecting a remote diagnostic device to a control network, as may beused, for example, in any of the remote diagnostic systems depicted inFIGS. 6 through 9, and

FIG. 11 is a block diagram illustrating an embodiment of a master buscontroller having two independent processors.

FIG. 12 is a diagram of a preferred handheld, computerized diagnosticdevice embodied as a personal digital assistant.

FIG. 13 is an example of a screen image depicting a vehicle outline inrelation to control network nodes and other features.

FIG. 14 is an example of a screen image depicting various controlnetwork components illustrated in a logic ladder format.

FIG. 15 is an example screen image of a main menu as may be used, forexample, in the computerized diagnostic device illustrated in FIG. 12.

FIG. 16 is an example of a logon screen as may be used, for example, inthe computerized diagnostic device illustrated in FIG. 12.

FIG. 17 is an example of a bus information input screen as may be used,for example, in the computerized diagnostic device illustrated in FIG.12.

FIG. 18 is an example of an input check select screen as may be used,for example, in the computerized diagnostic device illustrated in FIG.12.

FIG. 19 is an example of an output check select screen as may be used,for example, in the computerized diagnostic device illustrated in FIG.12.

FIG. 20 is an example of an RF test screen as may be used, for example,in the computerized diagnostic device illustrated in FIG. 12.

FIG. 21 is an example of a system help screen as may be used, forexample, in the computerized diagnostic device illustrated in FIG. 12.

FIG. 22 is a software architecture diagram as may be used in thecomputerized diagnostic device illustrated in FIG. 12.

FIG. 23 is an example of a logic ladder chart.

FIGS. 24, 25 and 26 are screen images illustrating activation of certaincontrol network components depicted graphically in a logic ladderformat.

FIG. 27 is a diagram of a local wireless communication network usefulfor monitoring, controlling, and/or tracking the position of portablewireless equipment used to remotely diagnose, test, and maintain controlnetworks.

FIG. 28 is a block diagram of one embodiment of a ground station as maybe deployed in a local wireless communication network.

FIG. 29 is a diagram of a diagnostic and maintenance system providingaccess by portable wireless equipment to a local area computer networkand a wide area network.

FIG. 30 is a diagram illustrating a particular embodiment of a localarea computer network as may be utilized, for example, in the system ofFIG. 29.

FIG. 31 is a process flow diagram illustrating steps in obtainingdiagnostic information alternatively from a local and remote source.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Various systems and methods for monitoring, controlling, diagnosingand/or testing a control network using portable, wireless equipment,will now be described in connection with preferred embodiments of theinvention.

FIG. 27 is a block diagram of one embodiment of a wireless diagnosticand control system 700 useful for monitoring, controlling and/ortracking the position of portable wireless equipment used to remotelydiagnose, test and maintain control networks. In accordance with apreferred embodiment as disclosed herein, a local area is generallyorganized into a plurality of separate regions or microcells 762, whichcollectively cover the entirety of the local region in which diagnosisand maintenance is to be carried out. A vehicle 702 may be brought intothe vicinity of the microcells 762 for diagnosis or maintenance. Thevehicle may be a conveyance of any type, such as, for example, a bus,light rail car, airplane or ship. Accordingly, the wireless diagnosticand control system 700 may be associated with a garage, railyard,airplane hangar, shipyard, or other area in which conveyances aretypically be brought for routine diagnosis or maintenance.

In a preferred embodiment, a plurality of ground stations 710, eachhaving an antenna 712, are dispersed in the microcells 762 so as toprovide wireless communication capability therein. The ground stations710, which are connected to a ground station interface 783 via landlines751 and thereby to a local area network (LAN) 754, may be connected bylandlines 713 in any suitable arrangement (e.g., serial chain, loop, orhub-and-spoke arrangements, to name a few). The ground stations 710provide wireless communication with portable electronic diagnosticequipment 730 within the region covered by the microcells 762. Theportable electronic diagnostic equipment 730 is preferably wireless innature, as represented symbolically in FIG. 27 by the antenna 731 whichis shown coupled to the portable electronic diagnostic equipment 730.The ground stations 710 may be located anywhere within the microcells762, depending in part upon the type of antennas 712 selected. Forexample, a ground station 710 may be located at the center of amicrocell 762 if it uses an omnidirectional antenna 712, or towards theedge of a microcell 762 if a directional antenna 712 is used.

The portable electronic diagnostic equipment 730 is preferably ofsufficiently small size that it may be conveniently carried around by anoperator. As the operator travels from microcell to microcell 762,communication may, in certain embodiments, be handed off from groundstation to ground station 710. The details of the handoff dependprimarily on the wireless communication protocol selected.Alternatively, each of the ground stations 710 may transmitsimultaneously, in which case a synchronization signal may be providedto each of the ground stations 710 via the landlines connecting them.

Each ground station 710 may have its own transmitting and receivingelectronics locally therein, allowing it to communicate independentlywith any number of portable electronic diagnostic devices 730.Alternatively, each ground station 710 may essentially comprise anantenna 712 used as a “listening post” (and transmitting beacon), withall data being carried to and from a centralized location (e.g., groundstation interface 783) for processing. Since the microcells 762 willordinarily be relatively small (depending upon the size of themaintenance area), the power level need for transmission by the groundstations 710 or the portable electronic diagnostic equipment 730 willnot be excessive. Since more than one operator carrying portableelectronic diagnostic equipment 730, the communications between thevarious portable electronic diagnostic equipment 730 (which may benumerous) and the various control networks 705 (which may also benumerous) are preferably distinguishable.

The ground station interface 783 provides a gateway to a local areanetwork 754. The local area network 754 may comprise, among otherthings, one or more user terminals 781 (e.g., user terminals 781 a and781 b), along with a diagnostic and maintenance information database780. As explained in more detail herein, supervisors or other personnelmay be stationed at the user terminals 781, and may thereby monitor orcontrol activity occurring within the region of the microcells 762, bycommunicating with the portable electronic diagnostic equipment 730.While monitoring, surveillance and control functionality is describedherein with respect to a local area network 754, it is also possiblethat such functionality could be included in a less sophisticated ormore elaborate system, for example, a single standalone workstationunder control of a single supervisor, or a larger, more expansive areanetwork.

The vehicle 702 is outfitted with an on-board control network 705, whichpreferably includes a wireless interface 720 and antenna 721 forcommunicating with the portable electronic diagnostic equipment 730and/or the ground stations 710. The control network 705 may comprise,among other things, a plurality of network nodes 740 for controlling theoperation and functionality of the vehicle 702. By way of illustration,the control network 705 may comprise any of the control network typesshown in FIG. 6, 7, 8 or 9, or any other type of control network.

The portable electronic diagnostic equipment 730 may be embodied in avariety of different manners. The portable wireless diagnostic equipment730 preferably comprises appropriate electronics (e.g., transmitter,receiver, and processor) to enable wireless communication with thecontrol network 705 located on-board the vehicle 702 and, moreparticularly, with the wireless interface 720 of the control network705. The portable wireless diagnostic equipment 730 also preferablycomprises appropriate electronics to enable wireless communication withthe ground stations 710 of the wireless diagnostic and control system700. In FIG. 27, a wireless communication link 715 between the portableelectronic diagnostic equipment 730 and a ground station 710 isillustrated, as is a wireless communication link 717 between theportable electronic diagnostic equipment 730 and the wireless interface720 of the control network 705. The control network 705 may also beprovided with appropriate electronics to enable wireless communicationwith the ground stations 710 of the wireless diagnostic and controlsystem 700, as illustrated by wireless communication link 716 in FIG.27. Either the same or different frequency bands and communicationprotocols may be used for wireless communication links 715, 716 and 717;however, in a preferred embodiment, the same frequency bands andcommunication protocols are used for each of wireless communicationlinks 715, 716 and 717, for reasons explained in more detail below.

The portable electronic diagnostic equipment 730 may be constructed as asingle, integrated device having both diagnostic functionality as wellas wireless communication capability with the control network 705 and/orthe ground stations 710 of the wireless diagnostic and control system700. In other embodiments, the portable electronic diagnostic equipment730 may comprise different mechanical units, each having a subset of theoverall functionality. By way of illustration, the portable electronicdiagnostic equipment 730 may be embodied as the combination of ahandheld, computerized diagnostic device (such as, e.g., the handheld,computerized diagnostic device or personal digital assistant 201 or 420shown in FIGS. 6 and 12, respectively) and a wireless intermediary unit(such as, e.g., wireless intermediary unit 205, 300 or 430 shown inFIGS. 6, 10 and 12, respectively). However, the portable electronicdiagnostic equipment 730 may also take many other forms. The portableelectronic diagnostic equipment 730 preferably comprises, among otherthings, a graphical display for displaying diagnostic and maintenanceinformation, a user interface (such as, e.g., a keypad, computer mouse,touchscreen, microphone/speaker with associated voice recognitionhardware and/or software, or the like), and a data storage module (anysort of volatile or non-volatile memory) for storing information neededfor performing diagnostic and maintenance functions.

Examples of operation of the wireless diagnostic and control system 700will now be explained. A vehicle 702 may be transported into themaintenance area covered by microcells 762 for diagnosis or maintenance.As illustrated in FIG. 27, the vehicle 702 may straddle severalmicrocells 762. If desired, more or fewer microcells 762 may be used,but having relatively small microcells 762 such that a vehicle 702 iscovered by several microcells 762 can have certain advantages. Inparticular, with small microcells 762, the wireless diagnostic andcontrol system 700 can track the location of the portable electronicdiagnostic equipment 730 and thereby allow dynamic selection of the mostuseful type of diagnostic information to provide to the portableelectronic diagnostic equipment 720 as it is carried around by anoperator. In one embodiment, for example, based upon the relativeposition of the portable electronic diagnostic equipment 730, theoperator is presented with the appropriate view of the control networkcomponents, on the graphical display of the portable electronicdiagnostic equipment 730. An example of a view of a vehicle that may bepresented to the operator is shown in FIG. 13. As the operator movesabout the vehicle 702, the view presented on the graphical display mayrotate along with the operator's position. To facilitate suchfunctionality, information concerning the position of the vehicle 702 isprovided to the wireless diagnostic and control system 700. Thisinformation may be obtained automatically, such as, for example, bymonitoring the wireless interface 720 of the control network 705 whenthe vehicle 702 is brought into the maintenance area. Such informationmay also be obtained straight-forwardly by use of position sensors (onthe walls, if any, and/or the ceiling or floor), or by manual input ofsuch information. In some environments, it may be desirable to requirethat the vehicle 702 be positioned in a certain space or berth, and in acertain specific orientation, so as to facilitate the acquisition of thevehicle position information.

The position of the operator may be determined at least in part usingthe received signal strength, or other signal quality metrics, of thesignal transmitted by the portable electronic diagnostic equipment 730.Near cell boundaries, comparisons of the signal quality metrics receivedat multiple ground stations 710 may be advantageously used to make moreprecise position estimates. Increasing or decreasing signal strengthsmay be used to indicate movement in position. While it may not benecessary, triangulation algorithms may also be used to locate theprecise position of the operator, based on information obtained from orreceived by multiple ground stations 710. Any necessary processing maybe carried out, for example, at the ground station interface 783, usingany suitable electronics (e.g., a microprocessor with digital signalprocessing capability). Techniques for determining relative receivedsignal strengths are well known in the art of wireless communications.

To provide assistance to the wireless diagnostic and control system 700for the purposes of displaying graphical images oriented in relation tothe operator's position with respect to the vehicle 702, the portableelectronic diagnostic equipment 730 may be provided with an interfaceallowing the operator to enter information concerning the operator'sview of the vehicle 702. For example, the operator may be provided witha selection of possible viewpoints (e.g., viewing towards front ofvehicle, viewing towards back of vehicle, viewing towards left ofvehicle, viewing towards right of vehicle, etc.), and may periodicallyselect one such viewpoint (as the operator moves about the vehicle)using the interface means provided at the portable electronic diagnosticequipment 730. This information may be relayed to the grounds stations710 and processed in connection with other position information. One ofthe user terminals 781, or some other hardware or software applicationin the local area network 754, may be designated to process the positioninformation to determine each operator's location. Based on all theavailable information, the local area network 754 transmits, via theground station interface 783, the position information back to theportable electronic diagnostic equipment 730.

In another embodiment, the ground stations 710 may each be configured toperiodically transmit an identifiable control signal which may be usedby the portable electronic diagnostic equipment 730 to determine itslocation among the various ground stations 710 using various signalquality metrics such as received signal strength. However, in such acase, the portable electronic diagnostic equipment 730 may need to beprogrammed with knowledge as to the geographical layout of the groundstations 710. In such an embodiment, the portable electronic diagnosticequipment 730 may also make use of any position information (e.g.,viewpoint) entered by the operator.

The diagnostic and maintenance information for the particular vehicle702 may, in some cases (particularly if there are many possible vehiclesto be serviced), be stored elsewhere than in the portable electronicdiagnostic equipment 730, due to possible memory constraints.Comprehensive diagnostic and maintenance information may be stored inthe diagnostic and maintenance information database 780 of the localarea network 754, and remotely accessed by the portable electronicdiagnostic equipment 730 as needed. In one embodiment, for example, theoperator may enter a vehicle identifier into the portable electronicdiagnostic equipment 730, which then retrieves the appropriatediagnostic and maintenance information from the local area network 754over wireless communication link 715.

The activity of operators using portable electronic diagnostic equipment730 may be monitored remotely at the local area network 754 throughwireless communication links 715 and/or 716. An advantage of using thesame frequency bands and communication protocols for each of wirelesscommunication links 715, 716 and 717 is that the data transmitted backand forth between the portable electronic diagnostic equipment 730 andthe control network 705 over wireless communication link 717 can bemonitored by ground stations 710, and relayed to the local area network754. Each diagnostic step or test procedure carried out by the operatorcan therefore be observed and, if desired, recorded at the local areanetwork 754. Each communication packet may contain an identifier of theportable electronic diagnostic equipment 730 (or equivalently, theoperator) and/or the particular vehicle 702. From such information,diagnostic records for each vehicle serviced may be maintained andperiodically updated at the local area network 754, providing a valuablesource of information for the maintenance provider. Also, security isenhanced, because the activity of operators can be directly monitored bysupervisors at user terminals 781 of the local area network 754.

In certain embodiments, supervisors may be provided with an ability toremotely override or shut down activity by particular maintenancepersonnel if deemed necessary. For example, if an operator has initiatedin inappropriate test, the supervisor may issue a command at a userterminal 781 which is relayed either or both the portable electronicdiagnostic equipment 730 and on-board control network 705, instructingthat the test be ignored, and possibly locking out further diagnostic ortest capabilities on a temporary basis. If desired, the graphicaldisplay of the portable electronic diagnostic equipment 730 may providean informational message to the operator that such action has beentaken.

Another use of the wireless diagnostic and control system 700 is thatmaintenance personnel can obtain, through the wireless connections,service advice from mechanics, electricians, engineers or othertechnical experts remotely located at a central location (i.e., thelocal area network 754).

FIG. 28 illustrates one possible embodiment of a ground station 800 asmay be used to assist with monitoring, controlling, and/or locatingportable electronic diagnostic equipment 730 within the maintenance areaof the wireless diagnostic and control system 700. As illustrated inFIG. 28, a ground station 800 may comprise an RF module 881 having atransmitter 887 and a receiver 889, connected to an antenna 890. Aprocessor 884 for controlling various operations and functions of theground station 800 is connected to the RF module 881, and is alsoconnected to a communications interface 883. The processor 884 isfurther connected to a memory 885, which stores data and one or moreapplication programs 886 in the form of programming code for executionby the processor 884. The memory 885 preferably comprises arandom-access memory (RAM) portion 898, and may also include a read-onlyportion where in the application programs 886 can be stored (althoughthe application programs 886 may alternatively be downloaded from thelocal area network 754 and stored in the local RAM portion 898 of thememory 885).

The communications interface 883 provides a wired (or possibly wireless)connection to the local area network 754. The communication interface883 may utilize any conventional data transport technique, and maycomprise, for example, a serial interface (such as an RS-232 orUniversal Serial Bus (USB) interface), a parallel interface, a fiberoptic interface, or any other suitable interface, using any conventionalprotocol for transporting data to and from the various ground stationsto the ground station interface 783. By way of illustration only, theground station interface 783 may comprise a ground communicationsprocessor which polls each of the ground stations 710 to determinewhether the ground station 710 has data to transport to the local areanetwork 754. Alternatively, the ground station interface 783 maycommunicate with the ground stations 710 in a prescribed sequentialorder, or may communicate with the ground stations 710 in parallel (overphysically separate channels), and may use any conventional multiplexingtechniques to ensure that data is smoothly transferred between theground station interface 783 and each of the ground stations 710. Theground station interface 783 may also, as previously noted, compriseelectronics for processing quality metrics associated with signalsreceived at the ground stations 710, to determine the position of theportable electronic diagnostic device 730 within the maintenance area.

Returning to FIG. 27, in accordance with one embodiment as disclosedherein, when an operator first activates a portable electronicdiagnostic equipment 730 or enters the maintenance area with the deviceactivated, the portable electronic diagnostic equipment 730 may scan oneor more set-up channels which are designated among the total channelscollectively utilized by the ground stations 710. Each ground station710 may be provided with its own unique set-up channel. The portableelectronic diagnostic equipment 730 may select one of the set-upchannels based upon various criteria (e.g., the strongest signalquality) and attempt to establish a bidirectional communication linkwith the ground station 710. Locking onto the strongest set-up channelusually results in selecting the nearest microcell 762. Once thebidirectional communication link between the portable electronicdiagnostic equipment 730 and the ground station 710 is established, arequest for service may be transmitted to the local area network 754 viathe ground station 710. The local area network 754 may respond by, e.g.,transmitting diagnostic or maintenance information retrieved from thediagnostic and maintenance information database 780 to the portableelectronic diagnostic equipment 730.

When the portable electronic diagnostic equipment 730 is transportedfrom one microcell 762 to another, if different communication channelsare used in different microcells, then a handoff of communication mayoccur whereby the bidirectional communication link is transferred fromone ground station 710 to another. Such a handoff may entail theportable electronic diagnostic equipment 730 changing operativefrequency band, time slot and/or code. Handoff may be controlled by theground station interface 783, which essentially acts in this context asa central station or ground station controller. Preferably, no more thanminimal interruption occurs to the communication link 715 between theportable electronic diagnostic equipment 730 and the ground station 710.Handoff may be initiated, in one embodiment, when the strength of thesignal received from the portable electronic diagnostic equipment 730falls below a certain level, thus indicating that the portableelectronic diagnostic equipment 730 is at or near a boundary of amicrocell 762.

Further details regarding the operation of the local wirelesscommunication network illustrated in FIG. 27 are described later herein;however, first presented below are details concerning various preferredembodiments of portable electronic diagnostic equipment 730 and controlnetworks 705, in order to allow fuller appreciation of the capabilitiesand functionality of the overall wireless diagnostic and control system700.

FIG. 5 is a diagram illustrating concepts of control network diagnosisand/or testing in accordance with a preferred embodiment as disclosedherein, as exemplified by a control network system deployed in a mobilevehicle 190 (in this example, a bus). As illustrated in FIG. 6, thevehicle 190 (shown in phantom) has a control network 199 (shown in dark,solid lines within the vehicle 190) for controlling circuitry and systemcomponents located throughout the vehicle 190, much the same as thecontrol network shown in FIG. 1. However, the control network 199 shownin FIG. 5 also includes a wireless diagnostic and maintenance linkingdevice (e.g., an radio frequency (RF) driver) 192 for providing awireless connection to portable wireless equipment utilized by anoperator 193. The wireless equipment preferably includes a handheld,computerized diagnostic device 194, such as a personal digital assistant(PDA) or similar device which is programmed to provide testing anddiagnostic functionality, and a wireless intermediary device 196. Thecomputerized diagnostic device 194 connects to the wireless intermediaryunit 196 by a connector cord 195 or other suitable means. The wirelessintermediary unit 196 is configured to communicate with the wirelessdiagnostic and maintenance linking device 192, thereby allowing wirelesscommunication between the computerized diagnostic device 194 and thecontrol network 199. The operator 193 can thus, for example, perform atleast all of the test and diagnosis operations that could be performedby connecting a test computer to the control network 199, but withoutbeing restricted as to mobility. The computerized diagnostic device 194also preferably includes further functionality as described herein.

FIG. 6 is a top-level block diagram of a remote diagnostic system 200 inaccordance with a preferred embodiment as disclosed herein. Asillustrated in FIG. 6, the remote diagnostic system 200 comprises aportable, computerized diagnostic device 201 (such as a personal digitalassistant (PDA)) which is connected to a wireless intermediary unit 205for the purpose of allowing wireless communication with a controlnetwork 218. The wireless intermediary unit 205 is configured tocommunicate with a wireless diagnostic and maintenance linking device215 which provides wireless access to the control network 218.

The control network 218 may take the form of any type of network, andmay include, for example, a hierarchical master-slave control networksuch as depicted in FIG. 2, a PLC-based control network as depicted inFIG. 3, a CAN bus or device net control network as depicted in FIG. 4,or any other type of control network, including control networks thatare fairly simple or substantially more complex than those depicted inFIGS. 2, 3 and 4. The wireless diagnostic and maintenance linking device215 may itself connect to an existing diagnostic and maintenance port(such as ports 129, 148 and 168 illustrated in FIGS. 2, 3 and 4,respectively) of the control network 218, thereby being compatible withcontrol networks 218 which have a built-in capability for connectingnon-wirelessly to a test computer.

FIGS. 7, 8 and 9 are diagrams illustrating concepts of the remotediagnostic system 200 shown in FIG. 6 as applied to various differenttypes of control networks 218. In FIG. 7, for example, is shown acontrol network system 240 wherein a handheld, computerized diagnosticdevice 241 (preferably embodied as a personal digital assistant (PDA))communicates with a hierarchical, master-slave control network 254 overa wireless communication link. The computerized diagnostic device 241 isconnected to a wireless intermediary unit 243 (preferably embodied as anRF driver) which preferably has, among other things, an antenna 244 forfacilitating wireless RF communication. The computerized diagnosticdevice 241 sends commands and other instructions in a digital format tothe wireless intermediary unit 243, which re-formats (if necessary) andmodulates the data over an RF communication link. The wirelessdiagnostic and maintenance linking device 247 (also preferably embodiedas an RF driver) receives the modulated data from the wirelessintermediary unit 243, demodulates the received data and places it in aformat compatible with the control network 254. In the example of FIG.7, the control network 254 includes an RS-485 compatible diagnostic andmaintenance port 248, and so the wireless diagnostic and maintenancelinking device 247 would place the received information in a formatcompatible with the RS-485 protocol. However, any other type ofinterface between the wireless diagnostic and maintenance linking device247 and the control network 254 may also be used.

In a similar fashion, the wireless diagnostic and maintenance linkingdevice 247 receives information from the control network 254, re-formatsthe information (if necessary) and modulates it for communication overan RF communication link (which may be the same or different RF channelas utilized on the forward link). The wireless intermediary device 243receives the modulated data from the wireless diagnostic and maintenancelinking device 247, demodulates the received data and places it in aformat compatible with the computerized diagnostic unit 241.

The control network 254 shown in FIG. 7 may comprise any hierarchical,master-slave network or loop configured network, and may have one ormore common buses, arranged in a single-tier (if one bus) or amulti-tier, hierarchical architecture. Illustrative (but not exhaustive)examples of various types of control network architectures that beincluded as part of the control network 254 are illustrated and/ordescribed in U.S. Pat. No. 5,907,486, Japanese Patent documents10-326259 and 10-333930, and U.S. patent application Ser. No. 08/854,160(entitled “Backup Control Mechanism In A Distributed Control Network”),Ser. No. 08/853,893 (entitled “Fault Isolation and Recovery In ADistributed Control Network”), Ser. No. 08/853,989 (entitled “Multi-TierArchitecture for Control Network”), and Ser. No. 09/442,368 (entitled“Control Network with Matrix Architecture”), all of which are assignedto the assignee of the present invention and hereby incorporated byreference as if set forth fully herein.

FIG. 8 is a diagram of a similar control network system 260 wherein ahandheld, computerized diagnostic device 261 (preferably embodied as apersonal digital assistant (PDA)) communicates with a PLC-based controlnetwork 274 over a wireless communication link. PLC-based controlnetworks have previously been described in general with respect to FIG.3, and thus a main control network CPU 270, main system bus 271, networknodes 272, and input/output modules 275 all generally correspond to thesimilar elements depicted in FIG. 3. Similar to the control networksystem 240 shown in FIG. 7, in FIG. 8 the computerized diagnostic device261 is connected to a wireless intermediary unit 263 (preferablyembodied as an RF driver) which preferably has, among other things, anantenna 264 for facilitating wireless RF communication. The computerizeddiagnostic device 261 sends commands and other instructions in a digitalformat to the wireless intermediary unit 263, which re-formats (ifnecessary) and modulates the data over an RF communication link. Awireless diagnostic and maintenance linking device 267 (also preferablyembodied as an RF driver) receives the modulated data from the wirelessintermediary unit 263, demodulates the received data and places it in aformat compatible with the control network 274. In the example of FIG.8, the control network 274 includes an RS-232 compatible diagnostic andmaintenance port 268, and thus the wireless diagnostic and maintenancelinking device 267 would place the received information in a formatcompatible with the RS-232 protocol. However, any other type ofinterface between the wireless diagnostic and maintenance linking device267 and the control network 274 may also be used.

A similar sequence of events occurs in the opposite direction to conveyinformation from the control network 274 to the wireless diagnosticdevice 261. Thus, the wireless diagnostic and maintenance linking device267 receives information from the control network 274, re-formats theinformation (if necessary) and modulates it for communication over an RFcommunication link (which may be the same or different RF channel asutilized on the forward link). The wireless intermediary device 263receives the modulated data from the wireless diagnostic and maintenancelinking device 267, demodulates the received data and places it in aformat compatible with the computerized diagnostic unit 261.

FIG. 9 is a diagram of another control network system 280 wherein ahandheld, computerized diagnostic device 281 (preferably embodied as apersonal digital assistant (PDA)) communicates with a CAN bus (or devicenet) based control network 294 over a wireless communication link. CANbus based control networks have previously been described in generalwith respect to FIG. 4, and thus a main CPU 290, CAN bus or device net291, CPUs 292, and I/O modules 295 all generally correspond to thesimilar elements depicted in FIG. 4. Similar to the control networksystems 240 and 260 shown in FIGS. 7 and 8, respectively, in FIG. 9 thecomputerized diagnostic device 281 is connected to a wirelessintermediary unit 283 (preferably embodied as an RF driver) whichpreferably has, among other things, an antenna 284 for facilitatingwireless RF communication. The computerized diagnostic device 281 sendscommands and other instructions in a digital format to the wirelessintermediary unit 283, which re-formats (if necessary) and modulates thedata over an RF communication link. A wireless diagnostic andmaintenance linking device 287 (also preferably embodied as an RFdriver) receives the modulated data from the wireless intermediary unit283, demodulates the received data and places it in a format compatiblewith the control network 294. In the example of FIG. 9, the controlnetwork 294 includes a CAN bus or device net compatible diagnostic andmaintenance port 289 and a CAN bus or device net gateway 288, and thusthe wireless diagnostic and maintenance linking device 287 would placethe received information in a format compatible with the CAN bus ordevice net gateway 288. However, any other type of interface between thewireless diagnostic and maintenance linking device 287 and the controlnetwork 294 may also be used.

A similar sequence of events occurs in the opposite direction to conveyinformation from the control network 294 to the wireless diagnosticdevice 281. Thus, the wireless diagnostic and maintenance linking device287 receives information from the control network 294, re-formats theinformation (if necessary) and modulates it for communication over an RFcommunication link (which may be the same or different RF channel asutilized on the forward link). The wireless intermediary device 283receives the modulated data from the wireless diagnostic and maintenancelinking device 287, demodulates the received data and places it in aformat compatible with the computerized diagnostic unit 281.

FIG. 10 is a diagram of a preferred wireless intermediary unit 300 forconnecting a remote diagnostic device to a control network, as may beused, for example, in any of the remote diagnostic systems depicted inFIGS. 6 through 9 (for example, as wireless intermediary unit 205, 243,263 or 283). As illustrated in FIG. 10, the wireless intermediary unit300 preferably comprises a communication interface 310 which connects bya cord 311 to a portable computerized diagnostic device (such as any ofthe computerized diagnostic devices 201, 241, 261 or 281 shown in FIGS.6, 7, 8 and 9, respectively). The nature of the communication interface310 depends upon the nature of the computerized diagnostic device, andmay be, for example, a serial interface (such as an RS-232 or UniversalSerial Bus (USB) interface), a parallel interface or fiber opticinterface. The communication interface 310 is connected to amicroprocessor 315 (which includes any necessary RAM, ROM or peripheralcomponents), which in turn connects to a communications module 325. Thewireless intermediary unit 300 also preferably comprises a powersub-system (unless it receives power from an external source, such asthe computerized diagnostic device), comprising a power supply 321, apower converter 320 and a power management circuit 322.

In a preferred embodiment, the communications module 325 communicatesover radio frequencies, and thus is, in essence, an RF module. Thecommunications module 325 preferably comprises a transmitter 236 and areceiver 327, and is preferably connected to an antenna 330. Thereceiver 327 may, for example, be a double conversion superheterodynevariety.

In operation, the wireless intermediary unit 300 acts as a wirelessinterface between a computerized diagnostic device and a controlnetwork. The wireless intermediary unit 300 receives information(preferably in a digital format) from the computerized diagnostic deviceover the communications interfaced 310, formats the information fortransmission, and modulates the information over a wirelesscommunication channel. The steps involved in formatting and modulatingthe information from the computerized diagnostic unit depend upon theformat in which the information is received, the format in which thereceiving device expects the information, and the nature of the physicallink (i.e., the wireless communication channel). If the communicationsinterface 310 to the computerized diagnostic device comprises a parallelinterface, for example, then the microprocessor 315 may convert theincoming parallel data into serial data to facilitate transmission bythe RF module 325. In any event, the microprocessor 315 and/or RF module325 may add header bits, error correction and/or encoding to the messagebeing transmitted. In the opposite direction, the RF module 325 and/ormicroprocessor 315 may demodulate, decode, error check and/or stripheader bits from information received over the wireless channel from thecontrol network.

In a preferred embodiment, the communications interface 310 comprises anRS-232 compatible interface, which has the advantage of allowingcompatibility with many personal digital assistant (PDA) devices. Themicroprocessor 315 and/or communications interface 310 are preferablyprogrammed so as to be compatible with a Windows CE™ or LINUX compatibleplatforms as may be used in the computerized diagnostic device to whichthe wireless intermediary device 300 is connected.

The RF module 325 may employ frequency modulation (FM) techniques and/orspread spectrum encoding and decoding of transmitted signals. Thefrequency band may be any that is suitable, such as, for example, 400MHz, 300 MHz, 900 MHz, or 2.4 GHz. The frequency band may be determinedby inserting the appropriate one of several RF module chips, or else maybe made selectable by the operator using switch settings. Avoltage-controlled oscillator (VCO) responsive to the switch settingsmay be used to generate the different frequencies. Alternatively, theswitch settings may affect both frequency settings and communicationprotocols, so that the same wireless intermediary device 300 can be usedfor different types of control networks using different wirelesscommunication interfaces. Each switch setting can correspond to aspecific control network type, and thus be associated with a specificfrequency band and communication protocol. The switch settings can beset manually through switches on the exterior of the wirelessintermediary device 300, or else may be selected through variousconfiguration options provided on the screen display of the computerizeddiagnostic device.

In one embodiment, the power sub-system provides power to thecommunication interface 310, microprocessor 315 and RF module 325. Apower supply 321 includes a battery (which can be alkaline or lithium(rechargeable), for example) or other low voltage power source. In apreferred embodiment, the power supply 321 comprises a 3.6 volt battery.A power converter 320 is provided to the voltage level of the 3.6 voltbattery to a 5 volt level suitable for the microprocessor 315 and RFmodule 325. The power management circuit 322, among other things,determines whether the battery level is high, medium or low. Thisinformation may be made available to the operator through one or moreLEDs, a gauge, or LCD display, for example. As an alternative to anon-board power supply 321, or in addition thereto, power may also bebrought into the wireless intermediary device 300 from an externalsource, such as the computerized diagnostic device.

The wireless intermediary unit 300 preferably includes a lightweight,durable moisture-resistant housing or encasement that may bemanufactured from any of a variety of materials, including, for example,plastic or aluminum (or other lightweight metal). The housing orencasement (not shown) of the wireless intermediary unit 300 preferablyincludes suitable means for allowing it to be physically carried by anoperator (thus facilitating its transportability), such as, for example,a belt clip, or small hoops for allowing the fastening of a strap ofsimilar means for securing the wireless intermediary unit 300 to thebody of the operator. Alternatively, the operator may wear a belt havinga pouch or pocket for placing the wireless intermediary unit 300.Because it is generally advantageous for an operator to be able to carryaround the wireless intermediary unit 300, it is preferably small insize, with on-board components integrated to the extent reasonablypossible. It should be possible to manufacture the necessary circuitryand components for the wireless intermediary unit 300 in a size similarto that of conventionally available cellular or pocket telephones, manyof which contain microprocessors, RF circuitry and a local power supply.

It should be noted that generally the wireless intermediary unit 300will connect to the computerized diagnostic device by a cord, cable,wire or other physical means, but in some circumstances a wirelessconnection between the wireless intermediary unit 300 and thecomputerized diagnostic device may be desirable, thus providing a“personal area network” associated with the operator.

Referring once again to the top-level block diagram in FIG. 6, inaccordance with one or more embodiments as disclosed herein, thecomputerized diagnostic device 201 is programmed to test, monitor and/ordiagnose a control network 218 by communicating to the control network218 through the wireless intermediary device 205. The computerizeddiagnostic device 201 preferably comprises a graphical screen displayfor displaying images, text and other information to the operator usefulfor testing, monitoring and/or diagnosing the control network.

An example of operation of the computerized diagnostic device 201 may beillustrated with respect to the control system 240 shown in FIG. 7,which, it will be recalled, depicts a hierarchical, master-slave controlnetwork 254. In this particular example, the master bus controller (MBC)250 of the control network 254 normally operates in a master mode withrespect to the common bus 251, while the other network nodes 252, 255normally operate in a slave mode with respect to the common bus 251. Themaster bus controller 250 preferably comprises a pair of independentprocessors 350, 351, a first processor 350 which connects to the commonbus 251, and a second processor 351 which connects to the diagnostic andmaintenance port 248, as illustrated in FIG. 11. The first processor 350acts as a master with respect to the common bus 251, while the secondprocessor 351 acts as a slave (i.e., listener) with respect to thediagnostic and maintenance port connection. Both processors 350, 351 areconnected to a dual-port RAM 355, which stores, among other things, atest mode status variable 356 indicating whether the master buscontroller 250 is in test mode or not. When a test, diagnosis or otheranalysis of the control network 254 is desired, the operator initiatesthe appropriate commands through the computerized diagnostic device(preferably using techniques described later herein), causing a modeswitch instruction to be relayed via the wireless intermediary device243 and wireless diagnostic and maintenance linking device 247 to themaster bus controller 250. The mode switch instruction is received bythe second processor 351, which interprets the instruction and, inresponse thereto, switches the test mode status variable 356 to indicatethat the master bus controller 250 is now in test mode. The firstprocessor 350 polls the test mode status variable 356 periodically(e.g., once per millisecond), and, when it observes that the state ofthe test mode status variable 356 has switched, enters the test mode.

Once the test mode is entered, the master bus controller 250 may operatewith reduced functionality as compared to its normal monitoring, commandand control duties, or may cease performing any monitoring, command andcontrol functions altogether, depending upon how it is programmed andthe criticality of those functions. The first processor 350 thencontinually checks for instructions sent from the computerizeddiagnostic device 241, which are relayed to it by the second processor351 and stored in the dual-port RAM 355 in predefined locations. Whenthe first processor 350 receives an instruction when in the test mode,it carries it out and awaits the next instruction. When the testoperation is complete (or when the wireless communication link isbroken), the second processor 351 returns the test mode status variable356 to its original (i.e., non-test mode) state. The first processor350, which continues to poll the test mode status variable 356 when inthe test mode, eventually observes that the test mode status variable356 has returned to its original state, and, in response thereto,resumes its normal monitoring, command and control duties.

A variety of other techniques may be used to cause the master buscontroller 250 to respond to instructions from the computerizeddiagnostic device 241. For example, the master bus controller 250 maycomprise only a single processor, and the wireless diagnostic andmaintenance linking device 247 may have direct memory access to a testmode status variable stored in the RAM of the master bus controller 250.Alternatively, the master bus controller 250 may receive an interruptfrom the wireless diagnostic and maintenance linking device, and maythen check a predefined instruction buffer to receive test instructionsoriginating from the computerized diagnostic device 241. A variety ofother techniques may also be used. Similar techniques may also be usedto initiate test mode operations with any other type of control network(including the control network systems 260 or 280 shown in FIGS. 8 and9, respectively).

Further functions and features of the computerized diagnostic device 201will now be described, with particular reference to FIG. 12, whichillustrates a preferred such device 201 embodied as a personal digitalassistant (PDA) 420, such as a commercially available PalmPilot® orother handheld computer device. While this embodiment is described withrespect to a PDA device, it will be understood by those skilled in theart that any other type of device having the same functionality may besubstituted for the PDA device.

In a preferred embodiment, the personal digital assistant 420 is basedon a platform running Windows CE®, LINUX, or another suitable operatingsystem 424 capable of supporting the operations of a handheld graphicalcomputing device. The personal digital assistant 420 also preferablycomprises a communication interface 428, which is used to communicatewith the wireless intermediary unit 430 through, for example, a directwired connection 432 (but alternatively, through a wireless connection434 such as a radio frequency (RF) or infrared (IR) connection). Thepersonal digital assistant 420 also preferably includes a graphicalscreen display 422, which may, for example, support a Graphical UserInterface (GUI) for allowing user interaction, and further includes oneor more application programs 426 which provide the programminginstructions for executing a variety of the test and diagnosticfunctions programmed into the personal digital assistant 420.

Some of the test and diagnostic functions that may be included are asfollows. The personal digital assistant 420 may allow the user to viewvarious aspects of the control network graphically on the screen display422. The displayed images may include, for example, illustrations of allor part of the control network within the context of the controlledfacility (e.g., a building, vehicle, plant, robot, machine or otherfacility), so as to facilitate the user's testing, monitoring and/ordiagnosis of the control network. The image of the facility may bepresented on the screen display 422 in a faint outline or phantomformat, while the control network may appear in solid, dark lines, thusallowing the user to easily distinguish the facility from the componentsof the control network being observed or tested.

The personal digital assistant 420 may also provide the ability for anoperator to force individual components in the control network system toa desired output state. By entering various inputs, the operator maycause test instructions to be conveyed wirelessly from the personaldigital assistant 420 to the control network 218, whereupon the testinstructions are relayed to the appropriate individual component(s) ofthe control network system. In the absence of any fault of componentfailure, the component should change states to the desired output statein response to receiving the proper instruction. The personal digitalassistant 420 may be programmed to receive feedback from the controlnetwork 218 over the wireless connection, and to display (in a ladderformat, e.g.) the states of the relevant switches, actuators or relaysalong the signal path to the network component being tested or observed.The personal digital assistant 420 may be programmed with informationpertaining to the locations of various network components in the controlnetwork 218 and their connectivity, thereby simplifying diagnosis ortesting by the operator, and reducing or eliminating the need for theoperator to carry and interpret bulky, cumbersome manuals and circuitblueprints.

The personal digital assistant 420 may also provide an automatedprocedure for testing the connection between it and the wirelessintermediary device 205 (or 430 in FIG. 12), and another automatedprocedure for testing the wireless connection between the wirelessintermediary device 205 and the control network 218.

Details of the above functions, and additional test and diagnosticfunctions, are provided below.

FIG. 22 is a diagram of a preferred software system architecture as maybe used in the computerized diagnostic device illustrated in FIG. 12. Asillustrated in FIG. 22, the software system architecture 600 comprises asecurity checking function 605, a main menu function 601, and a securityadministration function 607, which preferably (but need not)collectively comprise a software loop as illustrated. The main menufunction 601 calls any of a number of subsidiary functions, including anetwork information function 610, a help function 612, a power function613, a logo function 614 and an RF test function 615. All of theforegoing functions 601, 605, 607, 610, 612, 613, 614 and 615 may beviewed as “network independent” in the sense that they do not dependupon the nature of the control network being tested or diagnosed. Thenetwork information function 610 in turn accesses a variety ofadditional subsidiary functions, including a system check function 620,an input check function 621, a force output function 622, and areal-time monitoring function 623. These latter functions 620, 621, 622and 623 may be viewed as “network dependent” in certain aspects becausethey may depend or can be optimized for particular networkconfigurations, types or implementations. Further details regarding thesoftware functions appearing in FIG. 22 will be described or becomeapparent in the discussion of the test and diagnostic functions of thepersonal digital assistant 420.

A diagnostic system menu screen 460, as illustrated in FIG. 15,preferably allows a user to initiate various test and diagnosticfunctions relating to the control network 218, as well as to performvarious software system administrative functions. The test and diagnosisapplication software may have pre-programmed security functions designedto prevent unauthorized access to the diagnostic system main menu 460.Examples of security features are described below.

In a preferred embodiment, the security checking function 605 of thepersonal digital assistant 420 is invoked during initial user access,and also may be accessed via user selection of a security function iconfrom a diagnostic system main menu (see FIG. 15). The applicationprogram relating to the test and diagnosis features of the personaldigital assistant 420 may be launched according to any acceptableprocedure provided by the operating system 424, and is convenientlyaccomplished by user selection of an icon relating to the controlnetwork test and diagnosis application software. When a user initiallylaunches the control network test and diagnosis application software, orwhen the personal digital assistant 420 is powered on with thediagnostic system main menu 460 running, a logon screen 480, asillustrated in FIG. 16, is preferably displayed, prompting the user toenter a logon identification (ID) string in a user ID field 482 andpassword in a password field 484 in order to gain operational access tothe control network test and diagnosis application software. Thesecurity checking function 605 then attempts to verify the logon IDstring and password. If the security checking function 605 is able toverify the logon ID and password, the user is then allowed to access thescreen displaying the diagnostic system main menu 460, including theassociated test and diagnostic system functions. An example of adiagnostic system main menu is illustrated in FIG. 15. If the user'slogon ID and password cannot be verified, the user is denied access tothe features provided by the test and diagnosis application software.Preferably, the security checking function 605 also continuouslymonitors each individual user's activity, and logs off any user who hasbeen inactive for a predetermined period of time. This automatic log-offtimeout function reduces the likelihood that an unauthorized person canaccess the test and diagnostic application software by using a personaldigital assistant 420 which has not been properly logged off.

A variety of icons 461 through 472 are shown in the exemplary diagnosticsystem main menu 460 illustrated in FIG. 15. Rather than icons, textualstrings may be displayed, listing the various available functions. Theicons 461 through 472, however, are convenient from a user standpoint,and may be selected by, for example, a wand device, user contact (if atouch screen), pressing an appropriate keyboard key (for example,entering the first letter(s) of the desired function, or using the arrowkeys to the appropriate icon and pressing enter), vocalizing the desiredinput (if a microphone and speech recognition software are provided), orby any other selection means provided within the functionality of thepersonal digital assistant 420. The precise manner of selecting thevarious icons or functions of the test and diagnosis applicationsoftware is not important to the overall operation of the invention inits various embodiments as described herein.

A user may invoke various security functions by selecting the Securityicon 469 from the system main menu 460, shown in FIG. 15. If a user hasprivileges associated with a system administrator, then selecting theSecurity icon 469 from the main menu 460 may enable the user to performvarious system administration functions, such as, for example, adding anew user ID and password, deleting a user ID, or modifying an existinguser's password 484. If the user logs on using a standard user logon ID(as opposed to a system administrator user ID), selecting the Securityicon 469 from the main menu 460 may enable the user to perform certainsystem administrative functions unique to that individual, such as, forexample, modifying his or her existing password 484.

The diagnostic system main menu 460 illustrated in FIG. 15 isparticularly tailored, in this example, to the transit vehicle industry,but may be tailored to any industry, or else may be made generic. Inthis particular embodiment, however, a bus (i.e., transit vehicle)information icon 461 is provided as part of the diagnostic system mainmenu 460. Alternatively, the bus information icon 461 may be replaced bya control network information icon, to make its functionality moregeneric. A primary purpose of the bus information icon 461 is to allowthe user to identify which transit vehicle (i.e., bus) type will betested and/or diagnosed, and, further, which specific transit vehiclewithin that transit vehicle type will be tested and/or diagnosed.

When the user selects the bus information icon 461 from the diagnosticsystem main menu 460, a bus information input screen 490 is preferablydisplayed, as illustrated in FIG. 17. The user may then enter a transitvehicle type (or control network type, more generically) in a transitvehicle type field 492, and a transit vehicle identification (ID) number(or control network ID, more generically) in a transit vehicle ID field494, which identifies the particular vehicle (or other structure orfacility) to be serviced. The transit vehicle type 492 may be entered bythe user (using a numeric keypad in connection with a wand, forexample), or alternatively may be selected from a drop down menu(invoked by selecting a drop down menu button 496) listing availabletransit vehicle types. For any given transit vehicle type, manyindividual transit vehicles may exist. Entry of a unique transit vehicleID in the transit vehicle ID field 494 identifies the specific vehicleto be serviced. The network information function 610 (see FIG. 22)preferably manages the foregoing transit vehicle or control networkinformation functions. It preferably responds to the entry ormodification of the transit vehicle ID by verifying that the specifiedvehicle exists (i.e., is recognized by the test and diagnosisapplication software) and that a communications connection to thatvehicle can be established.

In a preferred embodiment, when the user has selected the specifictransit vehicle ID and it has been recognized by the network informationfunction 610, the personal digital assistant 420 attempts to communicatewith the control network 218 of the selected transit vehicle throughestablishment of a wireless connection by the wireless intermediary unit205 (or 430, as depicted in FIG. 12). If the control network 218 of thespecified transit vehicle does not respond to the wireless intermediaryunit 205 (or 430), then an error message may be displayed on the screenimage of the personal digital assistant 420, indicating a communicationslink failure. Such a failure may be caused by a variety ofcircumstances, including, for example, that 1) the specified transitvehicle is not within range of the wireless intermediary unit 205(possibly because an incorrect transit vehicle ID is entered), or 2) thecommunications link itself failed due to mechanical malfunction.

If the specified transit vehicle (or control network) type and transitvehicle (or control network) ID are verified by the network informationfunction 610, and, optionally, if a communications link is establishedto the control network 218, the network information function 610 maythen ensure that the relevant transit vehicle (or control network)information is available to the personal digital assistant 420. Forexample, the network information function 610 may examine a data storagecomponent (such as an internal ROM/PROM/EEPROM chip or memory card,including a plug-in “flashcard” or flash memory card, a CD-ROM, aninsertable memory cartridge, or a disk, to name a few examples) todetermine whether the relevant transit vehicle (or control network)information is available. The data storage component may storeinformation relating to a single transit vehicle (or control network),or multiple transit vehicles (or control networks). If the informationpertaining to the selected transit vehicle (or control network) is notfound on the data storage component, then the network informationfunction 610 may cause a message to be displayed on the display screen422 requesting the user to insert or otherwise provide the necessarydata storage component (i.e., “Please insert the memory cartridge [ormemory card] for the Alpha bus”). Alternatively, the user may downloadsuch information from a host computer (not shown).

As yet another alternative, the personal digital assistant 420 mayattempt to automatically download the control network information from aremote host computer. To this end, the personal digital assistant 420may be configured with its own wireless communication interface throughwhich it makes a connection to a remote host computer at which therelevant control network information is stored. For example, in relationto the wireless diagnostic and control system 700 illustrated in FIG.27, the personal digital assistant 420, which could be associated withone embodiment of the portable diagnostic equipment 730 in FIG. 27, mayconnect to the local area network 754 and download information from thediagnostic and maintenance information database 780. As a variation ofthis technique, the wireless intermediary device 205 (or 430) may beprovided with means for establishing a separate wireless communicationlink to a remote host computer at which the relevant control networkinformation is stored. For example, in relation to the wirelessdiagnostic and control system 700 illustrated in FIG. 27, the wirelessintermediary device 205 (or 430), which could be associated with oneembodiment of the portable diagnostic equipment 730 in FIG. 27, mayconnect to the local area network 754 and download information from thediagnostic and maintenance information database 780.

Assuming the transit vehicle (or control network) information isavailable to the personal digital assistant 420, the personal digitalassistant 420 returns to the main menu function 601 and displays thediagnostic system main menu 460 for the user to select desireddiagnostic functions to be performed on the vehicle.

Once the control network (e.g., transit vehicle) type and specific IDare selected, the user may thereafter perform a variety of test ordiagnostic activities utilizing the personal digital assistant 420. In apreferred embodiment, selection of a system check icon 462 allows theuser to graphically observe a diagram of the control network 218,preferably within the context of the associated transit vehicle or otherfacility (e.g., building, plant, robot, etc.). In a preferredembodiment, in response to selection of the system check icon 462, andas illustrated in FIG. 14, some or all of the network nodes 442 of thecontrol network 218 are graphically displayed on screen display 422 ofthe personal digital assistant 420 in dark, solid lines, superimposed ona three-dimensional (3-D) transparent or phantom outline image 440 ofthe transit vehicle (or other structure or facility which houses thecontrol network 218). Each of the network nodes 442 in the controlnetwork may be numbered or otherwise designated with a unique identifier(e.g., A1, A2, B1 and so on) for identification by the user. Graphicaldisplay in this manner assists the user in identifying and locatingvarious network nodes of the control network 218, by showing theirrelative positions within the image 440 of the transit vehicle (or otherfacility).

The graphical information relating to the image 440 and the networknodes 442 is preferably stored on (or downloaded to) a data storagecomponent within the personal digital assistant 420. As notedpreviously, this information may be stored in ROM, PROM, EEPROM, CD-ROM,memory cartridge, or any other data storage means accessible to thepersonal digital assistant 420. In a preferred embodiment, sufficientgraphical information is provided such that the image 440 of the transitvehicle (or other facility) is fully rotatable, thus allowing the userto change the view to correspond to wherever the user happens to bepositioned in relation to the vehicle. The user may be allowed, in someapplications, to zoom in or out of the screen image. Likewise,alternative view might be provided, such as an internal view versus anexternal view, and the user may be provided with means to select aparticular view.

Selection of the system check icon 462 by the user may also result in adiagnostic test being initiated by the system check function 620 (seeFIG. 22) of the application software running on the personal digitalassistant 420. For example, each of the network nodes 442 in the controlnetwork may be systematically tested by the control network, accordingto an instruction relayed from the personal digital assistant 420 to thecontrol network 218 over the wireless communication channel via thewireless intermediary device 205. This diagnostic test may run in acontinuous loop until terminated by the user by hitting, for example, anExit button 443. Control nodes 442 identified as malfunctioning duringthis diagnostic analysis may be illustrated on the screen display 422 ina distinguishable manner from properly functioning control nodes 442.This can be accomplished in various ways, such as by shading themalfunctioning control nodes 442 in a color different than the normallyoperating control nodes 442, or by causing the malfunctioning controlnodes 442 to blink on the graphical display 422, or by any other visualor graphical means. Detection of a malfunctioning control node 442during system check may also result in display of an error message onthe personal digital assistant 420 alerting the user of the problem.Once a malfunctioning control node 442 is serviced or replaced, thedisplayed error message is cleared, and the nature of the network nodeimage returns to its original display state.

While the image 440 of the transit vehicle or other facility ispreferably displayed transparently and in 3-D, in various applicationsthis type of graphical display may not be necessary or desired.Therefore, the image 440 being displayed may be a schematic diagram, ora two-dimensional image, if desired.

As further illustrated in FIG. 13, the image display software utilizedin connection with the check system function 620 also preferably allowsa text layer (such as “A1”, “A2”, “B1”, etc.) to be superimposed on theimage 440 appearing on the screen display 422. The text overlay may beused to provide identifying information for the various network nodes442, or to provide other information to the user.

Other additional functions preferably provided by the applicationsoftware run on the personal digital assistant 420 will now bedescribed. Returning to FIG. 15, user selection of the Input Check icon463 on the system main menu 460 causes the display of an input checkselect screen 500 (as illustrated in FIG. 18) on the screen display 422.The input check select screen 500 may comprise one or more pagesassociated with each network node, listing all of the testable inputswitches, actuators, relays, or other components associated with thenetwork node. In a preferred embodiment, a drop down menu 504 isavailable at the activation of a drop down menu button 502, that listsall of the available network nodes of the control network 218. Using thedrop down menu 504, the user selects a particular network node (e.g.,“AC-BO”) to be tested. Selection of a network node from the drop downmenu 504 results in one or more pages appearing on the input selectdisplay screen 500 listing all testable input components 506 associatedwith the selected network node. The user then indicates the inputcomponents 506 to be tested by selecting the corresponding check box(es)508 on the page of the input check select screen 500.

In response to selection of the check boxes 508 for the desired inputcomponents 506 to be tested, the application software of the personaldigital assistant 420 issues commands to the control network 218 (overthe wireless communication link, via the wireless intermediary device205) to check the status of the selected input components 506. Uponreceiving a response from the control network 218, the input checkfunction 621 of the application software highlights or otherwiseidentifies any malfunctioning input components 506 visually on the inputcheck select screen 500. The operator then may replace the indicateddefective input components 506, or otherwise locate the fault or causeof failure, to repair the malfunction. Remote testing of control networkinputs 506 in this manner is useful to the operator because oftencomponents 506 are located in hard to access places, particularly in thecontext of transit vehicles, as well as in many other applications. Thedrop down menu 504 on the input check select screen 500 is also usefulto the user as a directory to determine the names of input components506 and network nodes of the control network 218.

Returning once again to FIG. 15, user selection of the Output Check icon464 on the system main menu 460 results in a very similar sequence ofevents, and, initially, causes the display of an output check selectscreen 510 (as illustrated in FIG. 19) on the screen display 422. Theoutput check select screen 510 may comprise one or more pages associatedwith each network node, listing all of the testable output switches,actuators, relays, or other components associated with the network node.In a preferred embodiment, a drop down menu 514 is available at theactivation of a drop down menu button 512, that lists all of theavailable network nodes of the control network 218. Using the drop downmenu 514, the user selects a particular network node (e.g., “BA-IN”) tobe tested. Selection of a network node from the drop down menu 514results in one or more pages appearing on the input select displayscreen 510 listing all testable output components 516 associated withthe selected network node. The user then indicates the output components516 to be tested by selecting the corresponding check box(es) 518 fromthe first column of check boxes on the page of the input check selectscreen 510.

In response to selection of the check boxes 518 for the desired outputcomponents 516 to be tested, the application software of the personaldigital assistant 420 issues commands to the control network 218 (overthe wireless communication link, via the wireless intermediary device205) to activate all necessary input components (e.g., switches) toforce the selected output function. The application software of thepersonal digital assistant 420 then issues commands to the controlnetwork 218 (again over the wireless communication link, via thewireless intermediary device 205) to check the status of the selectedoutput components 516. Upon receiving a response from the controlnetwork 218, the output check function 622 of the application softwarehighlights or otherwise identifies any malfunctioning output components516 visually on the output check select screen 510. The operator thenmay replace the indicated defective output components 516, or otherwiselocate the fault or cause of failure, to repair the malfunction. As withthe Input Check function, the Output Check function provides the benefitof remote testing, which is very convenient for operational personnel.Further, the drop down menu 514 on the output check select screen 510 isalso useful to the user as a directory to determine the names of outputcomponents 506 and network nodes of the control network 218.

In the case of output state failure, the Output Check function of theapplication software running on the personal digital assistant 420allows interactive real time monitoring of the output functions 516. Thereal time monitoring function is activated by the user selecting theappropriate check box(es) 518 in the second column on the output checkselect screen 510 corresponding to the failed output 516. Real timemonitoring can also be selected directly from the diagnostic system mainmenu screen 460 shown in FIG. 15.

In a preferred embodiment, the real time monitoring feature of thepersonal digital assistant 420 preferably provides the ability todisplay a graphic, visual diagram, in “logic ladder” format, of theon/off states of selected control network components. Although manydifferent formats could be chosen, a logic ladder format is particularlyuseful for diagnostic and maintenance personnel. FIG. 23 is an exampleof a logic ladder chart, showing various conditions that are required toactivate a starter relay (“E3-3”). Such conditions, in this example,include at least the following: (1) alternator is not charging; (2)vehicle is in neutral; and either (3) the master switch is on, theignition and starter controller switches are set in front startpositions, and the starter button is on; or (4) the rear ignition andstarter switches are set in start position.

FIG. 14 shows a real time monitoring screen 450 displayed by theapplication software running on the personal digital assistant 420 inresponse to selection of the Real Time Monitoring function. The realtime monitoring screen 450 preferably displays a set of input elements456 (i.e., conditions) and the corresponding system output 458, in alogic ladder format. In this embodiment, the input elements 456 of thecircuit are highlighted to illustrate that the element is operatingproperly. This function allows real time monitoring of input componentsand output components within the control network 218.

In a preferred embodiment, a control module drop down menu 452 isavailable by selecting a drop down menu button 451, providing a list ofall network nodes of the control network 218. The user may therebyselect a particular network node for diagnostic testing. When a networknode is selected, a network node output drop down menu 453 is displayedby selecting a drop down menu button 454, providing a list of all systemoutputs for the selected network node. The user may then scroll throughthe list and select a particular system output to be tested using thereal time monitoring function.

In a preferred embodiment, the real time monitoring function displays agraphical diagram of the logic ladder format diagram including all inputelements 456 (i.e., conditions) required to activate the selected output458, displayed as symbols on the real time monitoring screen 450. Fromthe logic ladder diagram, the user then may individually select eachinput element 456 to perform real time diagnostic testing of each inputelement 456. If the element is functioning properly, then itscorresponding symbol on the real time monitoring screen 450 illuminatesor becomes otherwise visually distinguished. If the switch is defective,it will not illuminate or becomes otherwise visually distinguished in amanner indicated that it is not operating. This function allows fast andconvenient real time diagnostic monitoring of a complete circuit, fromthe input elements 456 to the system output 458, in all possible inputcombinations.

FIGS. 24, 25 and 26 show examples of screen images illustratingactivation of certain input elements depicted symbolically within alogic ladder format, eventually leading to activation of an outputcomponent (i.e., back-up light). In FIG. 24, the initial logic ladderdiagram is illustrated for the user on the screen display 422. The userthen may select the first input element or switch (“MBC-1”), causing itto become visually distinguishable, as illustrated in FIG. 25 (in thisparticular example, it becomes shaded, but it can as easily beilluminated or color coded as well). Then, the user may select thesecond input element or switch (“MBC-13”), causing it to become visuallydistinguishable, as illustrated in FIG. 26. When the inputs have been soactivated, the output state of the output component (i.e., backup light)can be checked.

To carry out the Real Time Monitoring function, as each input element isselected by the user, the application software sends the appropriatecommands across the wireless connection (via the wireless intermediarydevice 205 or 430) to the control network 218, which responds byactivating the appropriate switch or component. The control network 218can send a response to the personal digital assistant 420 as each switchor component is activated, or else the application software canperiodically poll the status registers at the control network todetermine when the switch or component has activated or reached itsdesired state.

As noted, the real time monitoring select function may be invoked for aparticular system output by selecting the check box 518 (in the secondcolumn) for the output 458 on the output check select screen 510, shownin FIG. 19. In response to selection of one or more real time monitoringoptions using the check boxes 518, the application softwareautomatically displays the real time monitoring select screen 450 on thescreen display 422 of the personal digital assistant 420, with thecorresponding logic ladder diagram (i.e., switch hierarchy) for theselected system output 458. When multiple system outputs 458 areselected, the application software may rotate through the correspondinglogic ladder diagrams sequentially, or may allow the user to scrollthrough them until the desired screen is found. Allowing direct accessfrom the Output Check function to the Real Time Monitoring functioneliminates the need for a user to select the network node and systemoutput 453 each time on the Real Time Monitoring select screen 450,thereby increasing the efficiency of testing multiple system outputs 458and their corresponding input elements 456.

Returning once again to FIG. 15, user selection of the RF Test icon 472(or communication link test icon) on the diagnostic system main menu 460displays an RF test screen on the personal digital assistant 420. Anexample of a preferred RF test screen 520 is shown in FIG. 20. The RFtest screen 520 preferably activates an RF test function, which verifiesthe integrity of the connection both between the personal digitalassistant 420 and the wireless intermediary unit 430, and the connectionbetween the wireless intermediary unit 430 and the control network 218.A simple checksum or other error detection technique may be used. Anyerrors detected in these communication links cause the RF test function615 of the application software to generate an error message on the RFtest screen 520 of the personal digital assistant 420, thereby alertingthe user of a potential problem.

Various miscellaneous features are also preferably provided inconnection with the test and diagnostic features. For example, returningagain to FIG. 15, user selection of a Power icon 467 on the diagnosticsystem main menu 460 may act to shut down the power to the personaldigital assistant 420. User selection of a Help icon 466 on thediagnostic system main menu 460 displays a system help screen 530 on thescreen display 422 of the personal digital assistant 420, an example ofwhich is illustrated in FIG. 21. The help screen 530 provides on-linehelp for the various functions provided by the test and diagnosisapplication software running on the personal digital assistant 420. Ascroll-down menu of help topics may be provided, from which the user maymake a selection in order to get further information on the topic.

The personal digital assistant 420 may be employed within a wirelessdiagnostic and control system 700 such as illustrated in FIG. 27. Insuch an arrangement, the portable electronic diagnostic equipment 730illustrated in FIG. 27 may be embodied as the personal digital assistant420 along with a wireless intermediary unit 430. Tracking of thelocation and/or movement of the portable electronic diagnostic equipment730, as previously described in connection with FIG. 27, enables certainfunctions useful to the operator to be performed during the diagnosisand maintenance of control network facilities. For example, one featureof a preferred personal digital assistant 420 that has been previouslydescribed is the ability to view various aspects of the control network705 graphically on the unit's screen display 422, where the image of thecontrol network facility (in this example, vehicle 702) is presented ina faint outline or phantom format, while the control network 705 withinthe vehicle 702 appears superimposed on the phantom image in solid, darklines, thereby allowing the operator to easily distinguish the facility(i.e., vehicle 702) from the components of the control network 705 beingobserved or tested. FIG. 13 illustrates an example of a phantom image ofa control network facility 440 (in this case a bus, corresponding tovehicle 702 shown in FIG. 27) with superimposed control network nodes442 (corresponding to network nodes 740 of control network 705 on-boardthe vehicle 702 shown in FIG. 27).

Through use of the wireless communication links previously described inconnection with the wireless diagnostic and control system 700 of FIG.27, the position of the portable electronic diagnostic equipment 730 (inthis example, personal digital assistant 420 and wireless intermediarydevice 430) relative to the vehicle 702 being serviced. Such adetermination may be made based in part on network configurationinformation stored in the local area network 754. The relevant positioninformation may then be used by the local area network 754 and/orpersonal digital assistant 420 to select from a plurality of availablegraphical displays showing the control network facility (i.e., vehicle702) from different positional perspectives. The local area network 754either then transmits the selected graphical display data back to thepersonal digital assistant 420, or else transmits the relevantpositional information to the personal digital assistant 420 to allow itto select the appropriate graphical display data, for presentation onthe diagnostic unit's screen display 422.

Such functionality allows the operator of the personal digital assistant420 to view the control network 702 on the portable diagnostic unitscreen display 422 from different positional perspectives, dependingupon the position of the operator relative to the control networkfacility 702. For example, if the operator stands behind vehicle 702 andactivates the previously-described system check function 620, the localarea network 754 is able to determine the position of the operatorrelative to the vehicle 702 based on the microcell 762 handling thecommunication link, along with other information as may be available(e.g., manually entered viewpoint information from the operator). Theresulting graphical display of the vehicle 702 would then be selected inan orientation with a view from the rear of the vehicle 702, since theoperator is standing behind the vehicle 702. If the operator moves tothe front of the vehicle 702, the system is able to track the movementof the operator and to select and transmit a different graphical displayof the vehicle 702 oriented in a different position—i.e., from the frontof the vehicle 702—or else to transmit positional information allowingthe personal digital assistant 420 to retrieve a new image or rotate thegraphical display image of the vehicle 702 so as to be properly orientedwith respect to the operator's new position.

The personal digital assistant 420 may, in certain embodiments, also beprovided with a zoom display function, whereby the operator may increaseor decrease the size of the graphical image on the screen display 422 ofthe personal digital assistant 420, to bring certain aspects of theimage into greater focus.

The variable-orientation (and zoom) graphical display capability of theportable electronic diagnostic equipment 730 should assist the operatorin more easily identifying and analyzing particular network nodes 740 ofthe control network 705, by providing particular focus on the networknodes 740 in closest proximity to the operator's position. It also mayhelp the operator in assessing problems with the control network 705 orlocating particular network nodes 740, because the image is displayedfrom the same perspective of the operator. Otherwise, particularly withlarge control networks 705 (such as may be contained in an airplane,ship or building), a single fixed display orientation of the controlnetwork 705 could prove visually confusing to the operator, especiallyfor nodes that are on the opposite side of the vehicle 702 or controlnetwork facility. By providing a variety of different perspective viewsof the control network 705 and vehicle 702, and displaying a selectedperspective view according in part to the position of the operator, itis more likely that the operator will achieve a direct, unobstructedview of a target area of the control network 705 for analysis,facilitating the diagnosis and testing of the various components of thecontrol network 705 (including components controlled by the controlnetwork 705).

In certain embodiments as described herein, remote monitoring andcontrol of the portable electronic diagnostic equipment 730 is carriedout with the assistance of the local area network 754, as illustrated inFIG. 27. Ground stations 710 arranged in the wireless diagnostic andcontrol system 700 may, in such embodiments, be used to monitor andcontrol the operation of portable electronic diagnostic equipment 730within the maintenance area.

Various applications programs may be executed on one or more userterminals 781 (or other computers) to provide end-user monitoring andcontrol functionality. As examples, the local area network 754 maymonitor and record each diagnostic or test transaction between theportable electronic diagnostic equipment 730 (in this example, personaldigital assistant 420) and the control network 705. Each diagnostic ortest operation, when transmitted by the portable electronic diagnosticequipment 730 or the wireless interface 720 of the control network 705,is intercepted by one or more of the ground stations 710 and relayedover to the local area network 754, where it may be recorded in thediagnostic and maintenance information database 780. Each suchtransaction may also be observed on one of the user terminals 781. Otheroperator interactions may also be recorded and separately transmitted tothe local area network 754. For example, when an incorrect useridentification or password is entered, the personal digital assistant420 may transmit this fact to the local area network 754.

Where multiple portable electronic diagnostic devices 730 are being usedin the same proximity, and where multiple control networks 705 and/orvehicles 702 are being serviced in the same proximity, it may beadvantageous to distinguish among communications from potentially manydifferent sources. One way to do so, for example, is to assign aseparate communication channel to each diagnostic and maintenancesession. In other words, a separate frequency, time slot and/or code(from a set of possible frequency bands, time slots and/or codes) may beassigned to the portable electronic diagnostic equipment 730 and thecontrol network 705 at the start of a diagnostic and maintenancesession. Such an assignment may be made by way of a separate controlchannel, for example. Thereafter, all communications for the particularsession will be carried out over the particular channel. The local areanetwork 754 instructs the ground stations 710 only to monitor assignedchannels, and can differentiate transmission sources based upon thechannel being used. As for distinguishing between the portableelectronic diagnostic equipment 730 and the control network 705 (whetheror not distinct frequencies, time slots, and/or codes are assigned),source identification information may be provided in message headers soas to enable the local area network 754 to identify the communicationsource. Such source identification information may be permanentlyassigned or built-in to each communication device, or else may betemporarily assigned by the local area network 754 each time a newcommunication device becomes operative in the maintenance area.

The local area network 754 thereby enables a “supervisor” (or even anautomated monitoring program) to perform various administrative,security, and quality control functions and operations. The local areanetwork 754 preferably monitors all portable electronic diagnosticdevices 730 in the maintenance area, and may keep track of, for example,the identification of each portable electronic diagnostic device 730 andits associated operator (based on, e.g., log-in information), thecontrol network 705 currently being serviced by each operator, eachdiagnostic or test transaction performed by each operator and theresults thereof, the sequence of diagnostic and test transactionsperformed by each operator, the starting and ending times and durationof each diagnostic and maintenance session, and any other informationuseful for administrative, security or quality control functions andoperations.

The information obtained from monitoring various portable electronicdiagnostic equipment in the wireless diagnostic and control system 700is preferably displayed to the supervisor at the local area network 754in real time on the display at one or more user terminals 781, therebyallowing monitoring of diagnostic and maintenance operations as they arebeing performed. If the supervisor decides it is necessary to terminateaccess to a control network 705 by a particular operator (for example,to prevent an illegal or inappropriate command), the supervisor mayenter an instruction at the user terminal 781 to do so. In response tosuch an instruction, a command is issued from one or more groundstations 710 to the control network 705 and/or the portable electronicdiagnostic equipment 730, causing the portable electronic diagnosticequipment 730 or control network 705 to take appropriate action toprevent further use by the operator. For example, either the portableelectronic diagnostic equipment 730 and/or the control network 705 mayterminate the diagnostic and test session and, if desired, lock out theparticular operator.

The tracking information obtained at the local area network 754 frommonitoring diagnostic and maintenance activity may be stored in a logfile for further processing or review. Reports can be produced from thelog files for quality control and work efficiency analysis. For example,based on the information stored in the log files, a worker productivityreport can be generated for each diagnostic technician, detailinginformation about the control networks 705 serviced, length of timerequired for each diagnostic session, and test and diagnostic functionscarried out during each diagnostic session.

In certain embodiments as disclosed herein, diagnostic and testfunctions similar to those carried out using the portable electronicdiagnostic equipment 730 are carried out remotely by technical personnelstationed at the user terminals 754. For example, most any of thediagnostic and test functions described with respect to the personaldigital assistant 420 shown in FIG. 12 can be performed using a displayand user interface at the user terminal 781, as opposed to the screendisplay 422 and user interface of the personal digital assistant 420.The wireless capability of the ground stations 710 provides thetechnical personnel at the local area network 754 with wirelesscapability similar to the wireless intermediary unit 430 connected tothe personal digital assistant 420. When used in conjunction with theportable electronic diagnostic equipment 730, the advantages of thewireless diagnostic and control system 700 are extended further, byallowing user terminals 781 of the local area network 754 to substitute,from a functional standpoint, for the portable electronic diagnosticequipment 730. If all of the portable electronic diagnostic devices 730happen to be in use or some become damaged or otherwise inoperable, atechnician can still perform remote diagnostic analysis on controlnetworks 705 at a user terminal 781 of the local area network 754,thereby causing no delays in maintenance and repair of control networkfacilities. Further, the advantages of allowing remote diagnosis andtest in harsh environments, without requiring human presence directly atthe control network 705, are readily apparent.

FIG. 29 is a diagram of a diagnostic and maintenance system 900providing access by portable wireless equipment and/or a wirelesscontrol network to a local area network and a wide area network (WAN),such as, e.g., the Internet. Similar to the system illustrated in FIG.27, one or more portable electronic diagnostic equipment 904 (preferablyeach embodied as a personal digital assistant (PDA) or similar handheldcomputerized equipment with wireless communication capability) are usedin connection with diagnosis, test and maintenance of one or morewireless control networks 906 each located in a mobile conveyance 908(e.g., a bus, automobile, train, airplane, ship, or the like), hereinreferred to simply as a vehicle, or located in other mobile orstationary location. The vehicle 908 is outfitted with an on-boardcontrol network 906, which preferably includes a wireless interface 910and antenna 912 for communicating with the portable electronicdiagnostic equipment 904. The control network 906 may comprise, amongother things, a plurality of network nodes 914 for monitoring theoperation and functionality of the vehicle 908 and its mechanicalcomponents. By way of illustration, the control network 906 may compriseany of the control network types shown in FIG. 6, 7, 8 or 9, or anyother control network type.

Also similar to the system described with respect to FIG. 27, theportable electronic diagnostic equipment 904 may be embodied in avariety of different manners. The portable electronic diagnosticequipment 904 preferably comprises appropriate electronics (e.g.,transmitter, receiver, and processor) to enable wireless communicationwith the control network 906 located on-board the vehicle 908 and, moreparticularly, with the wireless interface 910 of the control network906. The portable electronic diagnostic equipment 904 also preferablycomprises appropriate electronics to enable wireless communication witha local area network 922 via one or more ground stations 924. Forexample, the portable electronic diagnostic equipment 904 maycommunicate with one or more user terminals 925 through one or moreground stations 924 in a manner similar to that described with respectto the system of FIG. 27.

The portable electronic diagnostic equipment 904 may, for example, beconstructed as a single, integrated device having both diagnosticfunctionality as well as wireless communication capability with thecontrol network 906, and is preferably of sufficiently small size thatit may be conveniently carried around by an operator. In otherembodiments, the portable electronic diagnostic equipment 904 maycomprise different self-contained, mechanical units, each having asubset of the overall functionality. By way of illustration, theportable electronic diagnostic equipment 904 may be embodied as thecombination of a handheld, computerized device (such as, e.g., thepersonal digital assistant 210 shown in FIG. 6) and a wirelessintermediary unit (such as, e.g., the wireless intermediary unit 205shown in FIG. 6). Whether an integrated unit or different self-containedunits, the portable electronic diagnostic equipment 904 may includecircuitry for communicating wirelessly over a cellular telephone network935, in the alternative or in addition to circuitry for communicatingwirelessly with the one or more ground stations 924. As with variousexamples of embodiments previously illustrated herein, the portableelectronic diagnostic equipment 904 may comprise, among other things, agraphical display for displaying diagnostic and maintenance information,a user interface (such as, e.g., a keypad, computer mouse, touchscreen,microphone/speaker with associated voice recognition hardware andsoftware, or the like), and a data storage module for storinginformation needed for performing diagnostic and maintenance functions.

The local area network 922 preferably comprises, among other things, adiagnostic information database 930. The diagnostic information database930 preferably stores information useful in conducting diagnosis,maintenance, and/or testing of the on-board control network(s) 906.According to one embodiment, the portable electronic diagnosticequipment 904 obtains a control network (or vehicle) identifier byeither interfacing directly with the control network 906 or else havingthe information entered by an operator. The portable electronicdiagnostic equipment 904 then communicates with the local area network922 in order to pull diagnostic, maintenance, and/or test informationfrom the diagnostic information database 930 as needed to conductoperations as requested by the operator. It is contemplated that a largenumber of different control networks 906 can be serviced by the one ormore portable electronic diagnostic equipment 904, and therefore thediagnostic information database 930 can provide a useful aggregation ofdiagnostic, maintenance, and/or test information applicable to a largenumber of control networks 906.

The local area network 922 may further comprise a server computer 931which manages requests from various portable electronic diagnosticequipment 904, each of which may execute appropriate client software forinterfacing with the server computer 931. Based on, e.g., the controlnetwork or vehicle identifier, the server computer 931 may retrieve therequested diagnostic, test, or maintenance information from thediagnostic information database 930. For example, the server computer931 may, in response to an appropriate request, retrieve from thediagnostic information database 930 a list of test parameters,operational target values, parts numbers or attributes, diagrams, orgraphic and/or textual help or instructions to facilitate diagnosis,maintenance, and/or test of the control network 906. The server computer931 may also retrieve from the diagnostic information database 930 orelsewhere a set of configuration parameters or software code forre-configuring or re-programming the on-board control network 906.

The local area network 922 further preferably comprises a wide areanetwork (WAN) gateway 932, which connects to a wide area network 902such as the Internet. The user terminal(s) 925, server computer 931,and/or portable electronic equipment 904 may thereby access data atremote sites connected to the wide area network 902. Likewise, a remoteclient computer 907 may communicate with the local area network 922 overthe wide area network 902 in order to, e.g., access information from orupdate information in the diagnostic information database 930.

According to one embodiment, the server computer 931 facilitatesretrieval of information from not only the diagnostic informationdatabase 930, but also from various remote vendor computer systems(e.g., web sites) 955 which are accessible over the wide area network902. The remote vender computer system 955 may include, among otherthings, diagnostic and maintenance databases maintained by the vehiclemanufacturer, and/or links to other information sources providingdiagnostic, maintenance, and/or test information for the vehicle 908being serviced. In one aspect, the remote vender computer systems 955may comprise a virtual network of manufacturers and replacement partssuppliers who can be contacted via the wide area network 902 in order toobtain diagnostic or related information for selected vehicles 908, aswell as to allow ordering of replacement parts for any defective, spent,or inoperable parts detected during maintenance of the vehicle 908.

As one example of operation, the diagnostic information database 930 mayspecify a particular vendor with respect to a particular part used inthe control network 906 or on the vehicle 908. Based on the vendorinformation, the server computer 931 then may facilitate communicationbetween the portable electronic diagnostic equipment 904 and the remotevendor computer systems 955, so that the portable electronic diagnosticequipment 904 may, for example, retrieve parts data or other relevantinformation from the remote vendor computer systems 955. Likewise, theserver computer 931 may first check the diagnostic information database930 for certain diagnostic, maintenance, or test information and, if theinformation is not present, seek to retrieve or facilitate retrieval ofthe information from the remote vendor computer systems 955. Thisoperation is illustrated in the process flow chart of FIG. 31, wherein aprocess for retrieving diagnostic, maintenance, and/or test informationincludes the step 1903 of entering control network (or vehicle)identification information into the portable electronic diagnosticequipment 904, the next step 1907 of communicating a request forinformation from the local area network 922, the next step 1910 ofsearching and locating the diagnostic information in the diagnosticinformation database 930 if it is present and retrieving the informationin step 1912, or else requesting and retrieving the information from oneor more remote computer systems 955 over the wide area network 902 ifthe information is not present in the diagnostic information database930.

If the portable electronic diagnostic equipment 904 has wirelesscellular capability, then the portable electronic diagnostic equipment904 may directly contact the remote vendor computer systems via thecellular network 935. Cellular networks 935 presently supportInternet-based communication protocols, and therefore provide aninfrastructure useful for the portable electronic diagnostic equipment904 to retrieve information from remote vendor computer systems 955 inaccordance with the principles and concepts disclosed herein.

The system architecture illustrated in FIG. 29 may be used, in certainembodiments, to facilitate ordering of replacement parts either throughmanual orders or through an automated process. This aspect may beexplained in more detail with respect to the diagram shown in FIG. 30,in which the portable electronic diagnostic equipment 1804, groundstation(2) 1824, local area network 1822, user terminal(s) 1825, and WANgateway 1832 all have similar general functions to their counterpartsillustrated in FIG. 29. The system of FIG. 30 further illustrates theserver computer 1831 which interacts with the diagnostic informationdatabase 1830, as well as a replacement parts database 1872 and a jobauction database 1874. While the diagnostic information database 1830,replacement parts database 1872, and job auction database 1874 areillustrated as conceptually distinct databases in FIG. 30, their datamay be integrated or organized in any fashion in accordance with wellknown database management techniques.

When the test or diagnosis carried out using the portable electronicdiagnostic equipment 1804 reveals the need for one or more replacementparts, the portable electronic diagnostic equipment 1804 may convey thatinformation to the local area network 1822 and, in particular, to theserver computer 1831. The server computer 1831 then may check thereplacement parts database 1872 to determine which vendors provide thedesired replacement part(s). Based on that information, the servercomputer 1831 may be programmed to construct a job auction request whichis queued or otherwise stored in the job auction database 1874. Uponreceipt of the job auction request, or at specified periodic intervals,the server computer 1831 transmits bid requests based on the job auctionrequest particulars to the various remote vendor computer systems 955(see FIG. 29) via the wide area network 902. The bid requests mayinclude the desired part number, quantity, and any other usefulinformation (e.g., time window for return bid, time window for receiptof product, shipping terms, price ceiling, and so on). The remote vendorcomputer systems 955 then may process the bid requests and, if desired,return bids to the server computer 1831. The server computer 1831 maysimply accept the lowest price bid that meets the specified bid requestcriteria, or else may employ any type of auction process to carry out amore sophisticated bidding process. A wide variety of automated auctionprocesses are known in the art, and the details thereof are consideredwithin the purview of one skilled in the art.

If the server computer 1831 receives an acceptable bid, then the servercomputer 1831 may respond with an order request to the remote vendorcomputer system 955 providing the winning bid. If no bid is acceptable,the server computer 1831 may send a message to a system operator, orelse may revise the bid request terms according to pre-programmedcriteria and re-submit the bid request to the remote vendor computersystem 955. Similarly, the server computer 1831 may first send out thebid request to certain preferred vendors, and then, if the bid remainsunfulfilled within the prescribed time period, send the bit request outto other vendors.

In addition to the foregoing operations, the system 900 of FIG. 29 mayalso include a remote processing site 950 accessible via the wide areanetwork 902, whereby certain diagnostic, maintenance, and/or testoperations may be conducted. The remote processing site 950 may, in oneaspect, provide a centralized mechanism for servicing a number of localarea networks 922, thus providing the benefit of enhanced efficiency incertain respects. The portable electronic diagnostic equipment 904 may,if provided with wireless cellular communication capability, contact theremote processing site 950 directly via the cellular network 935, orindirectly via the local area network 922.

It is thus apparent that a wide variety of highly versatile and flexibleembodiments have been provided for remote monitoring, control, and/orlocating of portable electronic diagnostic devices, and for facilitatingdiagnosis, maintenance, and/or test of on-board or other types ofcontrol networks through the provision of diagnostic information, partsreplacement, and other means.

While preferred embodiments of the invention have been described herein,many variations are possible which remain within the concept and scopeof the invention. Such variations would become clear to one of ordinaryskill in the art after inspection of the specification and the drawings.The invention therefore is not to be restricted except within the spiritand scope of any appended claims.

What is claimed is:
 1. A method for facilitating diagnosis and maintenance of a vehicle system, comprising: obtaining diagnostic or test information using a portable, wireless handheld diagnostic device configured to detect electronic signals from a vehicle as an operator of the portable, wireless handheld device moves in or about the vehicle; durably storing the diagnostic or test information in a memory of the portable, wireless handheld diagnostic device; wirelessly transmitting the diagnostic or test information from the portable, wireless handheld diagnostic device to a remote vehicle database of a local area computer network, where the diagnostic or test information is associated with the specific vehicle; and in response to a user request, accessing the diagnostic or test information stored in the vehicle database from a user computer. 